track poller and daemon fds like the rest

src/daemon.rs

@@ -1,13 +1,15 @@
 use std::{
     env, io,
     ops::Deref,
-    os::fd::{AsFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd},
+    os::fd::{AsFd, BorrowedFd, IntoRawFd, OwnedFd, RawFd},
-    sync::LazyLock,
+    sync::{
+        LazyLock,
+        atomic::{AtomicUsize, Ordering},
+    },
     time::Duration,
 };
 
-use circular_buffer::CircularBuffer;
+use iddqd::{BiHashMap, IdOrdMap};
-use iddqd::BiHashMap;
 
 use mio::{Events, Interest, Poll, Token, net::UnixListener, unix::SourceFd};
 
@@ -21,7 +23,10 @@ use rustix::{
 use serde::{Deserialize, Serialize};
 use serde_json::StreamDeserializer;
 
-use crate::prelude::*;
+use crate::{
+    daemon_tokfd::{FdInfo, FdKind},
+    prelude::*,
+};
 
 use crate::{OwnedFdWithFlags, TokenFd};
 
@@ -98,12 +103,27 @@ pub enum DaemonCmd {
 
 const TIMEOUT_NEVER: Option<Duration> = None;
 
+static NEXT_TOKEN_NUMBER: AtomicUsize = AtomicUsize::new(1);
+fn next_token() -> Token {
+    let tok = NEXT_TOKEN_NUMBER.fetch_add(1, Ordering::SeqCst);
+
+    // If the increment wrapped to 0, then we just increment it again.
+    if tok == 0 {
+        return Token(NEXT_TOKEN_NUMBER.fetch_add(1, Ordering::SeqCst));
+    }
+
+    Token(tok)
+}
+
 #[derive(Debug)]
 pub struct Daemon {
     fd: OwnedFdWithFlags,
-    path: Box<OsStr>,
+    path: Option<Box<Path>>,
-    poll_error_buffer: CircularBuffer<ERROR_BUFFER_LEN, IoError>,
+
-    fd_error_buffer: CircularBuffer<ERROR_BUFFER_LEN, IoError>,
+    poller: Poll,
+
+    //fd_error_buffer: CircularBuffer<ERROR_BUFFER_LEN, IoError>,
+    fd_info: IdOrdMap<FdInfo>,
 
     // Bijective mapping of [`mio::Token`]s to [`RawFd`]s.
     tokfd: BiHashMap<TokenFd>,
@@ -114,9 +134,52 @@ pub struct Daemon {
 
 /// `tokfd` handling.
 impl Daemon {
-    //fn register(&mut self, token: Token, fd: RawFd) {
+    fn fd_error_pop(&mut self, fd: RawFd) -> Option<IoError> {
-    //    self.insert_unique
+        self.fd_info
-    //}
+            .get_mut(&fd)
+            .unwrap_or_else(|| {
+                if let Ok(name) = FdInfo::guess_name(fd) {
+                    panic!(
+                        "tried to pop error for unknown fd {fd} ({})",
+                        name.to_string_lossy(),
+                    );
+                }
+                panic!("tried to pop error for unknown fd {fd}")
+            })
+            .error_buffer
+            .pop_front()
+    }
+
+    fn fd_error_push(&mut self, fd: RawFd, error: IoError) -> Result<(), IoError> {
+        self.fd_info
+            .get_mut(&fd)
+            .unwrap_or_else(|| panic!("tried to push error for unknown fd {fd}"))
+            .error_buffer
+            .try_push_back(error)
+    }
+
+    fn register(&mut self, fd: RawFd) -> Token {
+        self.register_with_kind(fd, FdKind::Unknown)
+    }
+
+    fn register_with_kind(&mut self, fd: RawFd, kind: FdKind) -> Token {
+        let token = next_token();
+
+        self.fd_info.insert_unique(FdInfo::new(fd, kind)).unwrap();
+
+        self.tokfd
+            .insert_unique(TokenFd { token, fd })
+            .unwrap_or_else(|e| todo!("{e}"));
+
+        let mut source = SourceFd(&fd);
+        self.poller
+            .registry()
+            .register(&mut source, token, Interest::READABLE)
+            .unwrap_or_else(|e| unreachable!("registering {fd:?} with poller failed: {e}"));
+
+        token
+    }
+
     fn fd_for_token(&self, token: Token) -> Option<RawFd> {
         self.tokfd
             .get1(&token)
@@ -133,20 +196,38 @@ impl Daemon {
 }
 
 impl Daemon {
-    pub fn new(fd: OwnedFd, name_or_path: Box<OsStr>) -> Self {
+    pub fn new(fd: OwnedFd, kind: FdKind, name: Option<Box<OsStr>>) -> Self {
+        let mut fd_info: IdOrdMap<FdInfo> = Default::default();
+
+        // Supposedly, the only possible ways this can fail are EMFILE, ENFILE, and ENOMEM.
+        // If any of those are the case, we're screwed anyway.
+        let poller = Poll::new().unwrap_or_else(|e| panic!("can't create new mio::Poll: {e}"));
+        // Make sure we register the poller in `fd_info`, so we can keep track of its errors.
+        fd_info
+            .insert_unique(FdInfo::new(poller.as_raw_fd(), FdKind::Poller))
+            .unwrap_or_else(|e| unreachable!("{e}"));
+
         let fd = OwnedFdWithFlags::new_with_fallback(fd);
 
-        debug!(
+        fd_info
-            "opened daemon to {} file descriptor {fd:?}",
+            .insert_unique(FdInfo::new(fd.as_raw_fd(), kind))
-            name_or_path.display(),
+            .unwrap_or_else(|e| unreachable!("{e}"));
-        );
+
+        debug!("opened daemon to {:?} file descriptor {fd:?}", name);
+
+        let path = match &name {
+            Some(name) => Some(PathBuf::from(name).into_boxed_path()),
+            None => None,
+        };
 
         Self {
             fd,
-            path: name_or_path,
+            path,
-            poll_error_buffer: Default::default(),
+            poller,
+            //poll_error_buffer: Default::default(),
+            fd_info,
             tokfd: Default::default(),
-            fd_error_buffer: Default::default(),
+            //fd_error_buffer: Default::default(),
             cmd_buffer: Vec::with_capacity(1024),
             next_timeout: TIMEOUT_NEVER,
         }
@@ -162,7 +243,7 @@ impl Daemon {
         rustix::net::sockopt::set_socket_keepalive(&listener_owned_fd, true).unwrap();
         let path: Box<OsStr> = path.to_path_buf().into_boxed_path().into_boxed_os_str();
 
-        Ok(Self::new(listener_owned_fd, path))
+        Ok(Self::new(listener_owned_fd, FdKind::Socket, Some(path)))
     }
 
     pub fn open_default_socket() -> Result<Self, IoError> {
@@ -203,7 +284,7 @@ impl Daemon {
             .try_clone_to_owned()
             .expect("dynix daemon could not open stdin; try a Unix socket?");
 
-        Self::new(fd, Box::from(OsStr::new("«stdin»")))
+        Self::new(fd, FdKind::File, None)
     }
 
     //pub unsafe fn from_raw_parts(fd: OwnedFd) -> Self {
@@ -217,15 +298,13 @@ impl Daemon {
     }
 }
 
-const ERROR_BUFFER_LEN: usize = 8;
-
 /// Private helpers.
 impl Daemon {
-    fn read_cmd(&mut self, fd: Option<&dyn AsFd>) -> Result<(), IoError> {
+    fn read_cmd(&mut self, fd: &BorrowedFd) -> Result<(), IoError> {
-        let fd = match fd.as_ref() {
+        //let fd = match fd.as_ref() {
-            Some(fd) => fd.as_fd(),
+        //    Some(fd) => fd.as_fd(),
-            None => self.fd.as_fd(),
+        //    None => self.fd.as_fd(),
-        };
+        //};
 
         if self.cmd_buffer.len() == self.cmd_buffer.capacity() {
             self.cmd_buffer.reserve(1024);
@@ -247,12 +326,16 @@ impl Daemon {
                 },
                 Err(e) => {
                     warn!("error deserializing command: {e}");
-                    warn!("error count: {}", self.fd_error_buffer.len());
+                    debug!("command buffer was: {}", self.cmd_buffer.as_bstr());
+                    //warn!("error count for fd {fd:?}: {}", self.fd_error_buffer.len());
                     self.cmd_buffer.clear();
                     // Don't propagate the error unless we have too many.
-                    self.fd_error_buffer.try_push_back(e.into()).tap_err(|e| {
+                    self.fd_error_push(fd.as_raw_fd(), e.into()).tap_err(|e| {
                         error!("Accumulated too many errors for daemon fd {fd:?}: {e}")
                     })?;
+                    //self.fd_error_buffer.try_push_back(e.into()).tap_err(|e| {
+                    //    error!("Accumulated too many errors for daemon fd {fd:?}: {e}")
+                    //})?;
                     return Ok(());
                 },
             };
@@ -266,6 +349,17 @@ impl Daemon {
 
     pub(crate) fn enter_loop(&mut self) -> Result<Option<()>, IoError> {
         let raw_fd = self.fd.as_raw_fd();
+        if cfg!(debug_assertions) {
+            assert!(
+                self.fd_info.contains_key(&raw_fd),
+                "we should know about daemon fd {raw_fd}",
+            );
+            assert!(
+                self.fd_info.contains_key(&self.poller.as_raw_fd()),
+                "we should know about poller fd {}",
+                self.poller.as_raw_fd(),
+            );
+        }
         let mut daemon_source = SourceFd(&raw_fd);
         const DAEMON: Token = Token(0);
         self.tokfd
@@ -274,16 +368,9 @@ impl Daemon {
                 fd: raw_fd,
             })
             .unwrap();
-        let mut next_token_number: usize = 1;
-        let mut next_token = || -> Token {
-            let t = Token(next_token_number);
-            next_token_number = next_token_number.saturating_add(1);
-            t
-        };
 
-        let mut poll = Poll::new().unwrap_or_else(|e| unreachable!("creating new mio Poll: {e}"));
+        self.poller
-
+            .registry()
-        poll.registry()
             .register(&mut daemon_source, DAEMON, Interest::READABLE)
             .unwrap_or_else(|e| unreachable!("registering mio Poll for daemon fd {raw_fd:?}: {e}"));
 
@@ -297,18 +384,20 @@ impl Daemon {
                 );
             }
 
-            match poll.poll(&mut events, self.next_timeout.take()) {
+            match self.poller.poll(&mut events, self.next_timeout.take()) {
                 Ok(_) => {
                     if events.is_empty() {
                         warn!("timeout expired");
                         self.cmd_buffer.clear();
                     } else {
-                        let _ = self.poll_error_buffer.pop_front();
+                        //let _ = self.poll_error_buffer.pop_front();
+                        let _ = self.fd_error_pop(self.poller.as_raw_fd());
                     }
                 },
                 Err(e) => {
                     warn!("mio Poll::poll() error: {e}");
-                    self.poll_error_buffer.try_push_back(e).tap_err(|e| {
+                    self.fd_error_push(self.poller.as_raw_fd(), e)
+                        .tap_err(|e| {
                             error!("accumulated too many errors for mio::Poll::poll(): {e}")
                         })?;
                 },
@@ -324,7 +413,9 @@ impl Daemon {
                             .unwrap_or(false);
 
                         if !is_sock {
-                            self.read_cmd(None).unwrap();
+                            // SAFETY: oh boy: disjoint borrows with extra steps.
+                            let file_fd = unsafe { BorrowedFd::borrow_raw(self.fd.as_raw_fd()) };
+                            self.read_cmd(&file_fd).unwrap();
                             continue;
                         }
 
@@ -340,26 +431,27 @@ impl Daemon {
                             },
                             Err(e) => {
                                 error!("accept4 on daemon socket failed: {e}");
-                                self.fd_error_buffer.try_push_back(e.into()).tap_err(|e| {
+                                self.fd_error_push(self.fd.as_raw_fd(), e.into())
+                                    .tap_err(|e| {
                                         error!(
                                             "Accumulated too many errors for daemon fd {:?}: {e}",
                                             self.fd
                                         )
                                     })?;
+                                //self.fd_error_buffer.try_push_back(e.into()).tap_err(|e| {
+                                //    error!(
+                                //        "Accumulated too many errors for daemon fd {:?}: {e}",
+                                //        self.fd,
+                                //    )
+                                //})?;
                                 continue;
                             },
                         };
 
                         // Add this stream to our poll interest list.
-                        let mut stream_fd = stream_fd.into_raw_fd();
+                        // NOTE: `stream_fd` is now effectively `ManuallyDrop`.
-                        let token = next_token();
+                        let stream_fd = stream_fd.into_raw_fd();
-                        self.tokfd
+                        let _token = self.register(stream_fd);
-                            .insert_unique((token, stream_fd).into())
-                            .unwrap_or_else(|e| unreachable!("? {e}"));
-                        let mut source = SourceFd(&mut stream_fd);
-                        poll.registry()
-                            .register(&mut source, token, Interest::READABLE)
-                            .unwrap();
 
                         // Wait for the next poll to handle.
                     },
@@ -371,33 +463,26 @@ impl Daemon {
 
                         // SAFETY: oh boy.
                         let stream_fd = unsafe { BorrowedFd::borrow_raw(stream_fd) };
-                        self.read_cmd(Some(&stream_fd)).unwrap();
+                        self.read_cmd(&stream_fd).unwrap();
                     },
                 }
             }
         }
     }
-
-    //fn get_fallback_fd_name<Fd: AsRawFd>(fd: Fd) -> Option<Box<OsStr>> {
-    //    let dev_fd_path = Path::new("/dev/fd").join(fd.as_raw_fd().to_string());
-    //
-    //    fs_err::read_link(dev_fd_path)
-    //        .map(PathBuf::into_os_string)
-    //        .map(OsString::into_boxed_os_str)
-    //        .ok()
-    //}
 }
 
 impl Drop for Daemon {
     fn drop(&mut self) {
-        let probably_synthetic = self
+        //let probably_synthetic = self
-            .path
+        //    .path
-            .to_str()
+        //    .to_str()
-            .map(|p| p.starts_with("«") && p.ends_with("»"))
+        //    .map(|p| p.starts_with("«") && p.ends_with("»"))
-            .unwrap_or(false);
+        //    .unwrap_or(false);
-        if probably_synthetic {
+        //if probably_synthetic {
-            return;
+        //    return;
-        }
+        //}
-        let _ = rustix::fs::unlink(&*self.path);
+        if let Some(path) = self.path.as_deref() {
+            let _ = rustix::fs::unlink(path);
+        }
     }
 }

src/daemon_io.rs

@@ -6,8 +6,6 @@ use std::{
     },
 };
 
-use iddqd::BiHashItem;
-use mio::Token;
 use rustix::{
     fs::{OFlags, fcntl_getfl, fcntl_setfl},
     io::Errno,

src/daemon_tokfd.rs

@@ -1,8 +1,114 @@
-use std::os::fd::RawFd;
+use std::{os::fd::RawFd, sync::OnceLock};
 
-use iddqd::BiHashItem;
+use circular_buffer::CircularBuffer;
+use iddqd::{BiHashItem, IdOrdItem};
 use mio::Token;
 
+use crate::prelude::*;
+
+const ERROR_BUFFER_LEN: usize = 8;
+
+#[derive(Debug)]
+pub struct FdInfo {
+    pub fd: RawFd,
+    pub kind: FdKind,
+    pub name: OnceLock<Box<OsStr>>,
+    pub error_buffer: CircularBuffer<ERROR_BUFFER_LEN, IoError>,
+}
+
+impl FdInfo {
+    pub fn new<Fd: AsRawFd>(fd: Fd, kind: FdKind) -> Self {
+        Self {
+            fd: fd.as_raw_fd(),
+            kind,
+            name: Default::default(),
+            error_buffer: Default::default(),
+        }
+    }
+
+    pub fn new_with_name<Fd: AsRawFd>(fd: Fd, kind: FdKind, name: Box<OsStr>) -> Self {
+        Self {
+            fd: fd.as_raw_fd(),
+            kind,
+            name: OnceLock::from(name),
+            error_buffer: Default::default(),
+        }
+    }
+}
+
+impl FdInfo {
+    pub(crate) fn guess_name<Fd: AsRawFd>(fd: Fd) -> Result<Box<OsStr>, IoError> {
+        let dev_fd_path = Path::new("/dev/fd").join(fd.as_raw_fd().to_string());
+
+        fs_err::read_link(dev_fd_path)
+            .map(PathBuf::into_os_string)
+            .map(OsString::into_boxed_os_str)
+    }
+
+    pub fn name(&self) -> &OsStr {
+        if let Some(name) = self.name.get() {
+            return name;
+        }
+
+        match Self::guess_name(self.fd) {
+            Ok(name) => {
+                let prev = self.name.set(Box::from(name));
+                debug_assert_eq!(prev, Ok(()));
+            },
+            Err(e) => {
+                warn!(
+                    "can't read link for {} /dev/fd/{}: {e}",
+                    self.kind.name_str(),
+                    self.fd,
+                );
+                return OsStr::new("«unknown»");
+            },
+        }
+
+        self.name.get().unwrap_or_else(|| unreachable!())
+    }
+}
+
+impl IdOrdItem for FdInfo {
+    type Key<'a> = &'a RawFd;
+
+    fn key(&self) -> &RawFd {
+        &self.fd
+    }
+
+    iddqd::id_upcast!();
+}
+
+#[derive(Copy)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[non_exhaustive]
+pub enum FdKind {
+    File,
+    Socket,
+    SockStream,
+    Poller,
+    Unknown,
+}
+
+impl FdKind {
+    pub fn name_str(self) -> &'static str {
+        use FdKind::*;
+        match self {
+            File => "file",
+            Socket => "socket",
+            SockStream => "socket stream",
+            Poller => "poller",
+            Unknown => "«unknown»",
+        }
+    }
+}
+
+impl Default for FdKind {
+    fn default() -> FdKind {
+        FdKind::Unknown
+    }
+}
+
 #[derive(Copy)]
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct TokenFd {